<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <input type="text" v-model="msg">
        <h3>{{msg}}</h3>
        <h4>{{stus[0].name}}</h4>
    </div>
    <script src="./vue.js"></script>
    <script>
        new Vue({
            el:"#app",
            data(){
                return{
                    msg:'',
                    stus:[{name:'jack'}]
                }
            },
            watch:{
                msg:function(newV,oldV){
                    console.log(newV,oldV);
                }
            }
        });
    </script>
</body>
</html>